UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MAR - 2 2016 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

MEMORANDUM 

SUBJECT: 

FROM: 

THRU: 

TO: 

Paraquat: Potential Impacts of Proposed Mitigation Measurjr d 

Jonathan 

Bill Chism

Becker

, Ph.D.

, Ph.D.

, Senior 

, Senior 

Biologist 

Science Advisor 

b......,,l~~:.·~~r

./!/ --~ 

Sunil Ratnayake, Ph.D., Biologist ~ ~ 

Biological Analysis Branch l 

Derek Berwald, Ph.D., Economist (I __ ~ l,(J\ ~ Economic Analysis Branch ~ 

Biological and Economic Analysis Division 7503P) 

Colwell Cook, Ph.D., Acting Chief d4fvBiological Analysis Branch 

Timothy 

Economic Kiely, Analysis 

Chief 

Branch ~ , VV 

,, I\ 

\, \~ 

Biological and Economic Analys Division (7503 ) 

Marianne Mannix, Chemical Review Manager 

Tracy Perry, Team Leader 

Kelly Sherman, Chief 

Risk Management and Implementation Branch 3 

Pesticide Re-evaluation Division (7508P) 

Product Review Panel date: February 24, 2016 

Page 1 of9 
SUMMARY 

The EPA is proposing mitigation measures to minimize human health incidents associated with 

paraquat. Based on available data, BEAD estimates that the implementation of the proposed 

mitigation for paraquat will have the following impacts: Label amendments - no grower impact; 

closed systems - costs ranging from $500 to $700 per user that needs to upgrade their system, for 

a total of $12.5 million to $17 .5 million in one-time costs across all paraquat users; prohibition of 

hand-held application equipment - not estimated due to lack of data; restriction of use to 

certified applicators only - additional cost would be about $1.3 million annually across all 

paraquat users; development of paraquat-specific applicator training material - costs from $3, 100 

to $4, 700 per registrant. Important uncertainties associated with these estimates are described in 

the text. 

BACKGROUND 

Paraquat dichloride, a restricted use pesticide, is used as an agricultural herbicide and desiccant. 

This chemical is highly toxic to mammals through all routes of exposure and there is no known 

antidote for exposure to this chemical. Paraquat has been used as a suicide agent and there have 

been a large number of deaths resulting from the accidental ingestion of paraquat when 

compared to similar pesticides. The accidental ingestion incidents often result from paraquat 

being stored in beverage containers, contrary to clear label language prohibiting transfer into 

other containers. Paraquat is also corrosive to skin and is associated with a number of worker 

incidents involving exposure from equipment leakage or accidental contact with sprays in 

occupational settings. 

There have been multiple regulatory measures since the late 1980s to reduce the occurrence of 

accidental and intentional ingestion, including labeling and the incorporation of dyes, stenching 

agents, emetics, and gelling agents in the formulation. The 1997 Reregistration Eligibility 

Decision (RED) also required changes to lessen the occupational and ecological risks. 

In 2011 , EPA initiated the Registration Review process for paraquat, which noted a moderately 

high frequency of human health incidents. In 2013, the EPA received letters from the public 

noting that fatalities due to accidental ingestion were still occurring and calling on EPA to take 

action. The EPA responded to these letters and initiated an analysis of paraquat incidents. 

Based on the results of this analysis, the EPA is proposing additional mitigation measures to 

minimize human health incidents associated with paraquat. These measures are: (1) label 

changes emphasizing the toxicity of paraquat, (2) use of a closed-system (similar to the lock-andload system) for transferring paraquat out of all product containers, (3) prohibition of 

applications using hand-held equipment, (4) restricting the use of paraquat to certified 

applicators only (i.e., prohibiting application by individuals working under the supervision of a 

certified applicator), and (5) requiring the development of paraquat-specific applicator training 

material. 

This document considers the potential impact of the proposed mitigation measures based on 

currently available information. 

Page 2 of9 
POTENTIAL IMPACTS OF PROPOSED MITIGATION -

Label Amendments 

Mitigation measure: Paraquat labels will be amended to highlight ingestion risk, clarify toxicity, 

and add supplemental warning materials. 

Potential impacts: Because these label amendments highlight ingestion risk, toxicity, and add 

warning materials, BEAD does not anticipate impacts to the grower from these label 

amendments. 

Closed Systems 

Mitigation measure: The EPA is proposing to require all containers to be engineered so that 

paraquat must only be removed from the container using closed system technology meeting the 

following criteria: 1) The closed system must connect to the container in a way that the closed 

system is the only feasible way to remove paraquat from the container without destroying the 

container, 2) screw caps that can be removed allowing paraquat to be poured from the container 

are prohibited, and 3) the closed system must remove the paraquat from its original container and 

transfer the paraquat to the application equipment through connecting hoses, pipes and couplings 

that are sufficiently tight to prevent exposure of the mixer or loader to the paraquat, except for 

the negligible escape associated with normal operation of the system. The anticipated impacts of 

this mitigation measure on paraquat human health risk include the elimination of the opportunity 

for paraquat to be decanted into beverage (or any other inappropriate) containers and a reduction 

in spills and dermal exposure thus minimizing incidents resulting from improper use of PPE and 

the unsafe handling of paraquat. 

Potential impacts: Requiring closed systems would require users of paraquat who do not have 

closed systems to purchase them, and users with closed systems may need to pay for upgrades to 

bring the system into compliance with paraquat standards. For information on the cost of 

adopting a closed system for farmers, EPA contacted an industry representative who 

manufactures and sells closed systems and closed system components. The reported cost of a 

system that corresponded to the mitigation requirements was $500 to $700 per unit (Industry 

Communication, 2015). There is also a small additional cost for closures on the pesticide 

container that cannot be removed and mate with the closed system. As a baseline, EPA assumes 

that all growers and certified applicators will need to purchase a new system that meets the 

standards for the paraquat mitigation. Many growers and commercial applicators, particularly 

large ones, may already have closed systems to minimize exposure to pesticides from mixing and 

loading activities. However, we cannot assume that these existing systems will be compatible 

with what is required for paraquat. 

Based on available usage data, about 25,000 farms apply paraquat annually. Some of these 

farms may already have systems for handling pesticides that reduce the exposure to workers, 

handlers and applicators, but those systems may not be designed for and compatible with 

Page 3 of9 
closures for paraquat containers. If all of those growers need to pay for and install new 

equipment with a cost of $500 to $700, then the total, one-time cost to growers will be from 

$12.5 million to $17.5 million. There is a great deal of uncertainty around this estimate. Some 

growers, particularly large ones may have systems that are compatible with a new closure system 

for paraquat, or would face lower costs for adapting an existing system. It is also possible that 

other paraquat users, faced with expensive, one-time upgrade costs will either switch to 

alternative chemicals, or hire commercial pesticide applicators for paraquat treatment. It is also 

possible that paraquat manufacturers may subsidize the cost of new closed systems. 

These estimates are limited by uncertainties in these actual costs of closed systems, the number 

of applicators who would need to buy such systems, knowing whether existing systems would be 

compatible with new standard closures, and any training costs associated with closed systems. 

Prohibition of Hand Applications 

Mitigation measure: The EPA is proposing to prohibit the use of all hand-held application 

equipment, including backpack sprayers and hand gun sprayers, for paraquat. 

Potential impacts: Prohibition of hand-held equipment may cause growers to change to 

alternative chemical, or mixtures of chemicals to achieve similar weed control 

Paraquat is a rapidly acting, broad-spectrum, chemical used as an herbicide and as a desiccant, 

with relatively rapid-bum down efficacy. Survey and extension data suggest that hand-held 

applications of paraquat are made for weed control and not as a crop desiccant. Paraquat's 

combination of characteristics are not found in any other single alternative herbicide. The two 

herbicides with the most similar characteristics and use patterns to paraquat are glufosinate and 

glyphosate. Table l compares the characteristics of these three herbicides. 

Page 4 of9 
T a e bl 1 Ch f aractenstlcs o paraquat, g u l fi osmate, . an d l h g yp osate 

Characteristics Paraquat Glufosinate Glyphosate 

Weeds Selectivity Non selective Non selective Non selective 

Pre-plant Pre-plant Pre-plant Post directed Application No paraquat tolerant Post-emergence on Post-emergence on 

Liberty Link crops. Roundup Ready crops crops. 

Hand-held Permitted Permitted Permitted equipment 

Herbicide activity Contact Contact Systemic 

Coverage Complete coverage of Complete coverage of Complete coverage of 

foliage is needed foliage is needed foliage is not needed 

Activity Very rapid action Rapid action Slow action 

Rain-fastness 15 to 30 minutes 4 hours Varies by product (30 

min to several hours) 

Crop rotational 0 days Crop dependent Crop dependent 

interval (0 to 180 days) (0 to 30 days) 

Approximate cost 

per acre 

$7.00 $11.00 $5.00 

Based on extension publications, product labels, and Market Research Data ( 1998-2008). 

Depending on the particular combination of characteristics the grower requires, either glufosinate 

or glyphosate may be selected with a concomitant change in per-acre costs. Other growers will 

select a combination of active ingredients to provide the desired combination of characteristics. 

Currently it is not possible to quantify the impacts of switching to alternatives because of limited 

information on the use sites where hand-held application equipment is commonly used. The 

large number of herbicides that could be tank mixed to achieve similar characteristics also 

complicates the quantification. 

The use of small volumes of paraquat may indicate that growers use hand-held equipment. 

Paraquat is sold in several sizes of containers ranging size from one gallon to 2,000 gallons. The 

one gallon containers are only sold in Puerto Rico. Discussions with weed scientists in Puerto 

Rico suggest that paraquat is commonly applied by hand. If true, then the prohibition of handheld equipment in this area may have a larger regional impact. 

Restrict Use to Certified Applicators 

Mitigation measure: Paraquat dichloride is currently classified as a restricted use pesticide 

(RUP). As a RUP, paraquat can be used by certified applicators or those under their supervision. 

The EPA is proposing to restrict the use of paraquat to only allow certified applicators who have 

met the applicatory competency standards established by states, tribal, and federal agencies to 

use or handle paraquat. 

Potential impacts: This mitigation measure would increase costs to growers to the extent that 

certified applicators have a higher opportunity cost of time or charge more for application 

Page5of9 
services than those who currently apply paraquat under their supervision. The additional cost of 

this requirement can be estimated by the difference in wages between certified applicators and 

those they supervise. As part of the proposed revisions to the standards for certified applicators, 

OPP has estimated wage rates and the number of applicators by state for certified applicators and 

those who apply RUPs under their direct supervision (EPA 2015a). Certified pesticide 

applicators can either be commercial, when they apply pesticides for hire, or private if they apply 

pesticides on their own farm or without pay. The estimated cost for an hour of time is $52 for 

private certified applicators and $21 for commercial certified applicators. The difference in cost 

for these two is based on the cost of time being higher for private applicators, who are farmers 

and business owners. For uncertified applicators under the supervision of a certified applicator, 

the estimated wage rates are $18 for those supervised by commercial applicators, and $21 for 

those supervised by private applicators, (EPA 2015a, based on data from the Bureau of Labor 

Statistics). 

Available pesticide use data indicate that an annual average of 7.5 million acres were treated 

with paraquat as an herbicide from 2009 - 2014, and about 5 million of those acres were farmer 

applied; the remainder were applied by custom applicators or the applicator was not identified 

(Market Data Research, 2010-2014 ). In addition, paraquat is widely used as a desiccant on some 

crops, such as cotton and potato. The data available to EPA does not cover other desiccant uses, 

but for cotton and potato alone, about 1.9 million acres are treated with paraquat annually; about 

1.4 million acres (74%) of those acres are treated by the farmer, with the rest (about 500,000 

acres) treated by custom applicators (Market Data Research, 2010-2014). EPA does not have 

information on the acreage of other crops treated with paraquat as a desiccant. Taken together, 

this information reflects about 6.4 million acres treated by farmers, and about 3 million acres 

treated by custom applicators, which we assume to be commercial applicators. 

The difference in hourly cost is $31 for every hour of application being made by a certified 

private applicator instead of an applicator under their supervision, and $3 per hour for 

commercial applicators instead of an applicator under their supervision. To estimate the amount 

of application time that would need to be substituted, we begin with available pesticide usage 

data, which shows about 7.5 million acres treated with paraquat annually (Market Data Research, 

2010-2014). There are a range of estimates of the number of acres that can be treated by a 

sprayer in an hour's time. We use an estimate of 10 acres per hour (Iowa State University, 

2002), which corresponds to a 20 foot sprayer, the lowest reported in that study. This is a low 

estimate of the number of acres per hour that can be treated, which may correspond to a small 

sprayer in an orchard. Larger sprayers on field crops can apply faster; for example, 28 acres per 

hour on field crops in Illinois (University of Illinois, undated), 44 to 46 acres per hour in 

Minnesota (Lazarus, 2013), or 55 acres per hour in Iowa (Iowa State University, 2002). Using a 

low estimate of acres treated per hour will inflate the estimated costs of requiring all applications 

to be made by a certified applicator. 

If a sprayer can treat 10 acres per hour (Iowa State University, 2002), then nationally that 

requires 640,00 hours of applicator time by private applicators, and 300,000 hours by 

commercial applicators. If an applicator can treat 10 acres per hour, then substituting a certified 

applicator for an uncertified applicator under their supervision costs $3 .10 per acre for private 

applicators and $0.30 for commercial applicators. 

Page 6 of9 
To estimate the total cost of requiring application by certified applicators only, we need to 

estimate the number of acres treated with paraquat by certified applicators compared to those 

under their supervision. The Economic Analysis for the proposed changes to the certification 

standards estimated that there were about 82,000 private certified applicators nationwide, and 

about 2,800 noncertified applicators under their supervision (EPA 2015a). There were about 

414,000 certified commercial applicators, and 947,000 uncertified applicators under the 

supervision of a certified applicators (EPA 2015a ). If the ratio of non certified to certified 

applicators reflects the proportion of paraquat acreage treated by noncertified applicators, then 

about 3.3% of the 6.4 million acres treated annually by private applicators and about 70% of the 

3 million acres treated by commercial applicators are treated by uncertified applicators under the 

supervision of certified applicators. That implies that about 211 ,000 additional acres would need 

to be treated by private applicators at an additional cost of $3 .10 per acre, and an additional 2.1 

million acres would need to be treated by commercial applicators at an additional cost of $0.30 

per acre. 

The total additional cost from requiring only certified applicators to apply paraquat is $1.3 

million annually, almost -equally divided between private (about $650,000) and commercial 

(about $630,000), as shown in Table 2. 

Table 2. Estimated Cost of Restricting Application of Paraquat to Certified Applicators Only. 

Wage Cost Additional 

per Acre, at Estimated Cost for 

Wage 10 Acres per Acres Treatment by 

Rates Hour Treated Applicator* 

Private Certified Applicator $52 $5.20 6,190,000 $651,000 

Private Uncertified Applicator $21 $2.10 210,000 

Commercial Certified Applicator $21 $2.10 910,000 $627,000 

Commercial Uncertified Applicator $18 $1.80 2,090,000 

Total $1,278,000 

*The additional cost is the difference in cost per acre for substituting certified applicators times the numbers of 

acres treated by uncertified applicators. For private applicators, the difference in cost is $3 .10 per acre, and for 

commercial applicators $0.30 per acre. Labor rates are from 2013. 

Source: EPA Calculations, based on Market Research Data and EPA 2015a. 

There are important uncertainties with this estimate. The actual acreage treated with paraquat 

may differ, since EPA has little data on desiccant uses other than cotton and potato. The wage 

rates, especially for commercial applicators, may not reflect those of applicators applying 

paraquat in an agricultural section, as they were taken from a document that attempts to estimate 

the wages of all commercial applicators. Wages may differ for commercial applicators in lawn 

care, for example, and agricultural custom applicators. There are a range of estimates for how 

much acreage an applicator can treat in an hour, and we chose a relatively low one; higher 

treatment rates would lower the cost estimate. Also, we implicitly assume here that acreage 

treated by people supervised by private applicators will instead be treated by private certified 

Page 7 of 9 
applicators. It may be that, instead, commercial certified applicators will be hired at lower cost 

than private certified applicators. 

Paraquat-specific Applicator Training Material 

Mitigation measure: Given the highly toxic nature of paraquat and a history of misuse, EPA is 

requiring the technical registrants to develop comprehensive, paraquat-specific training materials 

for applicators. These training materials should consist of information highlighting paraquat 

toxicity and the risks associated with the use and misuse of paraquat in addition to appropriate 

handling, storage, disposal, and PPE requirements and instructions. All applicators handling 

paraquat dichloride should take the training which will be available online and retain 

documentation of successful completion. EPA' s intention is for the training website to be listed 

on all paraquat dichloride product labels and successful completion to be a condition of use. 

Potential impacts: For the proposed changes to the standards for certification of pesticide 

applicators, EPA estimated the cost of developing training materials (EPA 2015b) for certified 

applicators ranging from $3, 100 to $4,700, depending on the length of training required. The 

estimates were based on the amount of staff time it would take to revise the materials, with a 

staff wage of $39 per hour (EPA 2015b, based on information from the Bureau of Labor 

Statistics). The task of developing or adapting training materials for a 12 hour training session 

was estimated to take 100 hours of staff time, for a total cost of about $3,900 dollars every two 

years. We use that estimate for the cost of developing paraquat-specific training materials, as 

well. The estimate for the certification rule was based on materials were for training applicators 

on all the topics within a certification category, rather than just safe use of one particular 

pesticide. However, those costs were based on adapting existing material for training programs. 

Although safety information for paraquat and the closed systems already exist, they would need 

to be adapted. In addition, the mitigation proposal suggests that a website training be available, 

so 100 hours of staff time seems like an appropriate estimate. We do not include additional cost 

estimates for tracking or monitoring the status of certified applicators, however. The cost of 

$3,900 per developed training is a one-time cost, but it may need to be duplicated if more than 

one closed system is used for paraquat containers. 

References 

EPA 2015 . U.S. Environmental Protection Agency. Economic Analysis of the Agricultural 

Worker Protection Standard Revisions RIN 2070-AJ22. Docket: EPA-HQ-OPP-2011-

0184. September 2015. Available here: 

http://www.regulations.gov/contentStreamer?documentld=EP A-HQ-OPP-2011-0 l 84-

2524&disposition=attachment&contentType=pdf 

Page 8 of9 
EPA 20 l 5a. Economic Analysis of Proposed Amendments to 40 CFR Part 171: Certification of 

Pesticide Applicators. Docket ID: EPA-HQ-OPP-2011-0183. August, 2015. Available 

here: http://www.regulations.gov/contentStreamer?documentld=EPA-HQ-OPP-201 lO 18 3-004 3 &attachmentN umber= 1 &di sposi tion=attachment&content Type=pdf 

EPA 20 l 5b. Certification Rule Economic Analysis Appendix A: Detailed Information on Cost 

Estimates. August, 2015. Available here: 

http://www.regulations.gov/contentStreamer?documentid=EPA-HQ-OPP-2011-0 l 83-

0043&attachmentNumber=2&disposition=attachment&contentType=pdf 

Industry Communication, 2015. Proprietary pricing data provided by a manufacturer of 

chemical packaging and delivery systems, July 10, 2015 

Market Research Data (MRD) (1998-2008).Data collected and sold by a private market research 

firm. Data collected on pesticide use for about 60 crops by annual surveys of agricultural 

users in the continental United States. Survey methodology provides statistically valid 

results, typically at the state level. 

Giles, K, and R Billing. 2013. Designs and Improvements in Closed Systems. Report to K 

Everett, Pesticide Enforcement Branch, Department of Pesticide Regulations, California. 

13pp. 

Iowa State University, 2002. Estimating the Field Capacity of Farm Machines. April 2002. 

Available here: https://www.extension.iastate.edu/agdm/crops/pdf/a3-24.pdf 

Lazarus, William F. Machinery Cost Estimates, University of Minnesota Extension, June 2013. 

Available here: http://sheboygan.uwex.edu/files/2010/08/Machinery-Cost-Estimates.pdf 

University of Illinois, undated. Machinery Economics, FAST Tools and Resources. Available 

here: 

http://www.farmdoc.illinois.edu/fasttools/spreadsheets/programdescriptions/machineryec 

onomics.pdf 

Page 9 of9